Develop Reference

How to retrieve a specific row using SQLite and Cursors?

I want to retrieve a specific user from a SQLite database on Android with a provided username using a Cursor. I've tried this:
String[] fields = new String[] { "username", "email", "dateRegister" };
Cursor c = db.query(tableName, fields, "username ='1234'", null);
But it isn't working. How can I retrieve a specific row with the information of a unique column?

try this
db.query(tableName, null, "username = ?", new String[]{"username"}, null, null, null);

lots of guys asked the same question ,so please search efficient.
String query = "select * from " + tableName + " where "+ KEY_USERNAME + " = '" + uname + "'";
SQLiteDatabase sql = this.getReadableDatabase();
Cursor cur = sql.rawQuery(query, null);
return cur;

Getting completion suggestions from a database

I am trying to retrieve first 5 words from database and set those as text of button for that here is my code
String [] deal;
String text,s1,s2,s3,s4,s5;
text=edt.getText().toString();
deal=db.getAllItemFilter(text);
s1=deal[0];
s2=deal[0];
s3=deal[0];
s4=deal[0];
s5=deal[0];
sug1.setText(s1);
sug2.setText(s2);
sug3.setText(s3);
sug4.setText(s4);
sug5.setText(s5);
for database query i am using this code but it is not working
public String[] getAllItemFilter(String text)
{
String [] columns= new String[]{word};
Cursor cursor = this.ourdatabase.query(database_table, columns, " word like 'text%' ", null, null, null, null);
String [] deal = new String[cursor.getCount()];
int iword = cursor.getColumnIndex(word);
int i=0;
for (cursor.moveToFirst();!cursor.isAfterLast();cursor.moveToNext())
{
deal[i]=cursor.getString(iword);
i++;
if(i==5)
break;
}
return deal;
}
can anybody help me to get first 5 suggestions from database .Thanks in advance

you should first set a "LIMIT=5" at your SQL query end rather than a loop limit, it will save resources. Then you can replace word% by %word% to also match word beginning.

Your query is incorrect. As you have it set up, it is looking for "text*" every time (you forgot to format the query so the variable is used as a variable).
Change your cursor to what I show below if you want words beginnning with the supplied text:
Cursor cursor = this.ourdatabase.query(database_table, columns, " word like '" + text + "%' ", null, null, null, null);
If you just want words containing the supplied text, change it to:
Cursor cursor = this.ourdatabase.query(database_table, columns, " word like '%" + text + "%' ", null, null, null, null);

android sql - how do you order your sql query by multiple columns

I am currently working on an Android project in Eclipse and i am having problems with my SQL query.
I am trying to order the query by more than two columns, currently i am doing it by KEY_DAY_ID but i want to also do it by KEY_START_TIME, but i can't get it to work
my query currently looks like this:
Cursor cursor = db.query(TABLE_SESSION, new String[] {KEY_ID, KEY_MODULE_CODE,
KEY_DAY_OF_WEEK, KEY_START_TIME, KEY_DURATION, KEY_SESSION_TYPE, KEY_ROOM},
null, null, null, null, KEY_DAY_ID + " ASC");
Please let me know your thoughts. Thank you in advance!

The last parameter in db.query() method is the order by clause (without the "order by"). All you need to do is separate both columns by a ",". So it would look like:
Cursor cursor = db.query(TABLE_SESSION, new String[] {KEY_ID, KEY_MODULE_CODE,
KEY_DAY_OF_WEEK, KEY_START_TIME, KEY_DURATION, KEY_SESSION_TYPE, KEY_ROOM},
null, null, null, null, KEY_DAY_ID + " ASC, " + KEY_START_TIME + " ASC");

This works for me
SQLiteCursor cursor = (SQLiteCursor) db.query(DbHelper.TIMES, colmn, null, null, null, null, DbHelper.TABLE_DAY + " ASC, " + DbHelper.TABLE_LECTURE_NO + " ASC",null);

Also you can do it in select line like this:
Cursor data = ddbb.rawQuery("SELECT * FROM vacations ORDER BY NAME ,MONTH , date ",null);
in previous code the first probability for the first column "NAME" then will start arrange by the Second probability "MONTH" then the third "date".....
which mean working in series
Or:
Cursor data = ddbb.rawQuery("select * from vacations where NAME = ? ORDER BY MONTH AND date ",new String[]{ns});
in previous code by using "AND" the two conditions are working together in parallel

Is it possible to have sqlite query that seraches for two keys?

All the examples I see for doing a query show only using one key. Is it possible to use two keys. I have tried the code below and it does not work. I am trying to find the row where date and time match the date and time in the table
public String getPrimaryID(int date, int time )
{
Cursor c= db.query(DB_TABLE, new String[]{KEY_ROWID}, "date="+date+ "time=" + time, null, null, null, null);
int id=c.getColumnIndex(KEY_ROWID);
String result=c.getString(id);
return result;
}

I think you need to AND your query:
Cursor c= db.query(DB_TABLE, new String[]{KEY_ROWID}, "date="+date+ " AND time=" + time, null, null, null, null);

try this :
Cursor c = db.query(TABLENAME, null, "date = ? AND time = ?", new String[] { date, time }, null, null, null, null);
or :
String query ="SELECT * FROM " + TABLENAME + " " + "WHERE "
"date = ? " +
"AND time = ? ";
Cursor c = db.rawQuery(query, new String[] {date, time});
Explanation : variables date and time will replace the ? characters on the query

Android; I only have 2 contacts, yet I can obtain 5 from a query, why?

I have setup 2 test contacts in my emulator.
I'm running the following query, it should pick them both out, populate my domain object, and add to a list. The output at the bottom should therefore be 2, but it is 5, why is this? (cursor.getCount() is 5 instead of 2)
I have stepped through each iteration of the while loop and it is retreving the same contact multiple times, but with different values for POSTCODE, such as the phone number
ContentResolver cr = getContentResolver();
Cursor cursor = cr.query(ContactsContract.Data.CONTENT_URI,
null, null, null, null);
List<MeCercanaContact> contacts = new ArrayList<MeCercanaContact>();
if (cursor.getCount() > 0)
{
while (cursor.moveToNext())
{
MyContact myContact = new MyContact();
String givenName = cursor.getString(cursor.getColumnIndex(
ContactsContract.Contacts.DISPLAY_NAME));
String postcode = cursor.getString(cursor.getColumnIndex(
ContactsContract.CommonDataKinds.StructuredPostal.POSTCODE));
myContact.setFirstName(givenName);
myContact.setLastName(postcode);
contacts.add(myContact);
}
}
System.out.println(contacts.size());

After API 21 We Write this Query for remove contact duplicacy.
String select = ContactsContract.Data.HAS_PHONE_NUMBER + " != 0 AND " +
ContactsContract.Data.MIMETYPE
+ " = " + ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE + "
AND "+ ContactsContract.Data.RAW_CONTACT_ID + " = " +
ContactsContract.Data.NAME_RAW_CONTACT_ID;
Cursor cursor = mContent.query(ContactsContract.Data.CONTENT_URI, null, select,
null, null);

You are querying ContactsContract.Data, which is a generic container that holds a list of various contact details, such as phone numbers, postal codes etc.. You must filter the results for the rows whose ContactsContract.Data.MIMETYPE column equals StructuredPostal.CONTENT_ITEM_TYPE:
So change the query to:
Cursor cursor = cr.query(ContactsContract.Data.CONTENT_URI,
null, null, ContacsContract.Data.MIMETYPE + "='" +
ContactsContract.StructuredPostal.CONTENT_ITEM_TYPE + "'", null);
See ContactsContract.Data

a contact that is registered to multiple groups will show up multiple times
if you query the Uri CONTENT_URI = ContactsContract.Data.CONTENT_URI
Add this to your SELECTION:
+ ContactsContract.Data.DATA1 + " = 1 " ; //show only contacts in group 1